The Outliers in the Woods: Buckthorn, Honeysuckle, Multiflora Rose

After an October frost or two, the leaves on many of our woodland plants have changed color or fallen, and it’s a great time of year to scavenge the woods for the color green. In a healthy Iowa woodland, the conspicuous green foilage in October and November often belongs to the outliers: non-native, invasive shrubs and plants such as European Buckthorn, Garlic Mustard, Asiatic Bush Honeysuckle, Multiflora Rose, or Reed Canary Grass.

A  Perspective on Invasive Species

While native plants have gradually adapted to this place and tend to live in relative harmony with the insect, bird and wildlife species, non-native invasives tend to suppress biodiversity and can sometimes become destructive to the healthy functioning of the existing community.

Some of the invasive species that humans have intentionally and unitentionally shuttled across the ocean with blinding speed now rob our ecosystems of richness that I happen to appreciate. They violate the popular ecological view expressed through Aldo Leopold’s land ethic: “A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise.” In some fashion, the populations of my fellow two, four, six, eight, and ten-plus legged critters rooted in this place seem to feel an unspoken appreciation for biodiversity.

Since we selectively, and perhaps unfairly introduced these species onto the landscape, I believe it is fair to selectively remove them –  in a way that also seeks “to preserve the integrity, stability, and beauty of the biotic community”.

Removal Method

My preferred method of treating invasive shrubs is the cut-stump treatment. I use a Silky handsaw, brush cutter sawblade, or chainsaw to cut the stump, and a Buckthorn Blaster to apply a solution of herbicide mixed with dye around the perimeter of the stump.


Note: This list is ranked, approximately, from greatest to least threat in Iowa .

  • Worst Invasives. Species currently causing the greatest problems in Iowa forests.
    • European Buckthorn (Rhamnus cathartica)
      • 2013-11: Identified 650+ plants. Mapped, cut and treated all large stems with Pathfinder II, an herbicide with triclopyr  as the active ingredient
    • Garlic mustard (Alliaria petiolata)
      • First identified in 2010 or 2011, have continued a campaign to pull, spray, and burn patches of Garlic mustard through 2021
    • Asiatic bush honeysuckles (Lonicera spp)
      • 2013-11: First Identified. Treated several, many remaining and unmapped.
      • 2014-2: Cutting and treating stumps with Pathfinder II.
    • Multiflora rose (Rosa multiflora)
      • 2013-11: First identified, three plants
    • Reed canary grass (Phalaris arundinacea)